Meta is seeking a Research Engineer to work on frontier AI and real-world product impact within Facebook's ecosystem. The role involves building post-training, evaluation, and serving systems for LLMs, developing an agentic platform, optimizing systems through fine-tuning, and adapting these across Meta's products. The position offers end-to-end ownership, the opportunity to work on unsolved research questions with product consequences, and high autonomy in shaping technical direction for GenAI products used by billions.